Marketplace.tf Sales:

https://marketplace.tf/items/342;5;u7

https://manic.tf/keyprice/?at=2019-01-04 - $28.41 / $1.76 = 16.14 keys

https://manic.tf/keyprice/?at=2019-01-07 - $26 / $1.76 = 14.77 keys

X = 16

X = 15

Other Sales:

https://backpack.tf/item/215002989 (#1-7)

#1

Untraceable, not convinced the seller is legit anyways

https://backpack.tf/profiles/76561197968951769#!/compare/1547683200/1547942400

https://backpack.tf/profiles/76561198337734785#!/compare/1547856000/1547942400

#2

Untraceable

https://backpack.tf/profiles/76561198337734785#!/compare/1548028800/1548115200

https://backpack.tf/profiles/76561197998898020#!/compare/1548028800/1548115200

#3

Gambled

https://backpack.tf/profiles/76561198312441398#!/compare/1548115200/1548201600

https://backpack.tf/profiles/76561198179607307#!/compare/1548115200/1548201600

#4

Gambled probably

https://backpack.tf/profiles/76561198179607307#!/compare/1549065600/1549497600

https://backpack.tf/profiles/76561198376749531#!/compare/1548201600/1549670400

#5

Untraceable

https://backpack.tf/profiles/76561198376749531#!/compare/1549670400/1550275200

https://backpack.tf/profiles/76561198002757046#!/compare/1549584000/1549670400

#6

13 keys?

https://backpack.tf/profiles/76561198002757046#!/compare/1549584000/1549670400

https://backpack.tf/profiles/76561198196410274#!/compare/1549584000/1549670400

I’m fairly certain that more keys were involved, but we can’t see them here.

#7

Untraceable

https://backpack.tf/profiles/76561198196410274#!/compare/1549670400/1549756800

https://backpack.tf/profiles/76561197968968337#!/compare/1549670400/1549756800

Sellers:

https://i.imgur.com/n27Ikfu.png

https://backpack.tf/item/215002989 - 18 keys

https://backpack.tf/item/4043981979 - 22 keys

Sales at:

15

16

Going with 15-16.